1. Field of the Invention
The present invention relates to illumination of keyboards, keypads, and other data entry devices.
2. Description of the Relevant Art
Keyboards, keypads, mouses, and other data entry devices (hereinafter referred to generally as keyboards) are used in a variety of applications for entry of alphanumeric and other types of data into a machine such as a calculator or computer. Keyboards have been developed that are light weight, low in cost, and relatively easy to manufacture. However, difficulty has been encountered in the development of illuminated keyboards that are light weight, low in cost and easy to manufacture. For example, methods have been developed which require placement of a light source below and in proximity of each key of the keyboard, and each of these light sources must be connected to a power supply, rendering the manufacture of such a keyboard difficult and expensive. Another method for illuminating a keyboard requires a single light source that provides light to each key by means of optical light paths. The optical light paths are difficult to construct in order to illuminate the keys uniformly and efficiently. These methods have the disadvantage of requiring considerable power for illumination, an important consideration for laptop computers and calculators operating under battery power. Moreover, all of these methods are unsuitable for many of the new keyboards that have been developed which are not flat, such as ergonomic keyboards that arc upward and outward from a horizontal surface. More generally, none of the methods of the prior art are readily adaptable to existing keyboard manufacturing processes. Thus, the manufacturing process for manufacturing ordinary non-illuminated keyboards cannot readily and easily be adapted to the manufacture of illuminated keyboards.